Our Macy--a yellow lab mix weighing about 60 lbs--has ACL issues. We are trying to avoid surgery & tried this. We didn't notice any difference in how she moved. It is certainly possible that her problems were too serious for this to help with but several months after we stopped using this--she has shown a lot of improvement. Not sure if she just needed time to heal or if our recent move (with a change of climate) made any difference.